Stress Analysis of Friction Stir Spot Welded Magnesium Alloy Sheet under Tensile-Shear Load

The strength, failure location and modes of AZ31B Magnesium sheets with 1.5 mm thickness, joined using friction stir spot welding (FSSW), can be determined using tension-shear tests. However, the joined materials have different tension test and elastic-plastic characteristics. Elastic analysis methods for spot welding have been examined in detail in literature. However, if the material has narrow elastic and large plastic area characteristics, such as AZ31B, elastic-elastic analysis methods are deficient. The development and application of elastic-plastic analysis methods are required for such soft metal materials. In this study, the elastic-elastic and elastic-plastic analytical stress mechanisms were investigated. Strain and force equations were then derived using an analytical approach. These developed equations were based on the FSSW-Tension-Shear-Test and verified using Finite Element Method (FEM)-Analysis and tension-shear tests. In addition, the location of failure was also determined. It is possible to predict failures without performing tension-shear tests using the proposed analytical equations.